In the absence of special noise reduction treatment, loud, objectionable, harsh, and unwanted noise from engine combustion may travel thru the air induction system and may egress from the avenue(s) of air ingress.
Efforts have been made to reduce the levels of audible noises from various engine systems. For example, the noises produced from the flow of induction air flowing through an induction passage and through a turbo compressor on its way to the engine combustion chamber(s) are often addressed by fitting an inlet silencer to the compressor wheel inlet to attenuate the sound waves produced as air accelerates into the compressor. U.S. Pat. No. 6,736,238 provides an air intake silencer configured to reduce turbulence in the air flow from the silencer to the intake of the compressor. The patent discloses a housing containing a plurality of axially spaced annular noise attenuating baffles. The baffles define a series of axially spaced generally annular partial flow passages such that air flowing through the silencer is initially split and then merges into the axial outlet passage. The dimensions of the annular partial flow passages are made to vary so that the velocity of air flow through the passages is greater for passages closer to the axial outlet aperture.
The inventors of the present application have recognized a number of problems with the above approach. For example, the disclosed approach merely seeks to reduce noises generated from within the intake passage, specifically noises due to turbulence in the intake flow, and not noises that come from the engine. However, embodiments in accordance with the present disclosure provide an induction passage noise attenuator and a system that attenuates audible noise emitted from the engine.
Various embodiments in accordance with the present disclosure may provide a series of surfaces that may be directed inward and may therefore present a relatively smooth path for sound waves to travel inward. For sound waves that may be directed outwardly, a series of pockets between and/or among the series of surfaces may be provided. In this way, at least one path along which noise may travel from the engine may be made “rough” and may be otherwise more disruptive to sound waves that may be emitted from the engine.
Various embodiments in accordance with the present disclosure may provide a noise attenuator, or noise filter, that may be placed directly in line with the clean side air duct. In this way, the noise attenuator and/or noise filter may be positioned at an area of concentrated noise. In this way, embodiments provided in accordance with the present disclosure may operate at relatively easy to achieve levels of efficiency, for example 50% or less efficiency.
Embodiments may provide an induction passage noise attenuator that may include a series of surfaces arranged within an enclosure upstream from a clean side air duct on an induction inlet for an internal combustion engine. Each surface of the series of surfaces may have a diametric extent being substantially in line with an inner diameter of the clean side air duct.
Other embodiments may provide an induction passage noise attenuator that may include an enclosure having a central axis. The enclosure may have an enclosure inside surface that may be a second radial distance from the central axis. The enclosure may be configured to be disposed upstream from a clean side air duct. The clean side air duct may be fluidically coupled with an intake passage for an internal combustion engine. The clean side air duct may have a clean side air duct inner surface that may be a first radial distance from the central axis. A series of surfaces may be arranged in the enclosure. Outer edges of each of the series of surfaces may be disposed at a third radial distance from the central axis. The third radial distance may be substantially equal to (e.g., within 5%), or greater than, the first radial distance and less than the second radial distance.
Other embodiments may provide a system. The system may include an intake air passage for passing intake air to an engine including an upstream passage and a downstream passage. The downstream passage may have a first inner diameter. An enclosure may be fluidically coupled at an upstream side thereof to receive the intake air from the upstream passage, and fluidically coupled at a downstream side thereof to pass the intake air to the downstream passage. The enclosure may have a second inner diameter bigger than the first inner diameter. A series of surfaces may be located within the enclosure. Each surface of the series of surfaces may have an outer diameter greater than or substantially in line with the first inner diameter. For example, the surface may have a center that is in line with the first inner diameter.
Embodiments may provide a series of surfaces that may be directed inward and may present a relatively smooth path for sound waves to travel inward toward the engine, specifically toward the intake manifold. The series of surfaces may also provide a series of pockets between adjacent surfaces. In this way a “rough” path which may be disruptive to the sound waves may make it more difficult for sound waves to travel from the engine and out through the induction passage.
In some embodiments the precise size of the enclosure, or chamber, the positioning of the chamber, and/or design of various other features may be optimized for different engines and vehicle lines. Among other thing in this way, smooth, even, and gradual air flow, may be provided which may produce low resistance, which may be important for air induction system performance, and/or engine performance.
Various embodiments may include a sonically porous filler material, such as fiberglass strands, or the like. The material may allow a certain amount of sonic penetration. The material may also act to gradually absorb, attenuate, and diffract sound waves. The material may also serve to discourage efficient reflection of sound waves off internal walls. With various embodiments the filler material, and/or the filler material characteristics, may be advantageously selected for one or more particular applications. An example advantageous selection may include varying the density along the chamber.
Various embodiments described herein may place a single chamber directly in line with the noise path. In this way, a broad band of noise may be attenuated. Systems and devices in accordance with various embodiments may be placed in a convenient location within the engine compartment. Embodiments may help reduce or avoid using complex, expensive, iterative, mathematical analysis of the engine/induction system. In this way, costs may be reduced among other advantages.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.